1. Field of the Invention
The invention relates to a circuit arrangement and a method for starting internal combustion engines by means of a starting repeat in case of a blockage of the meshing drive.
2. Prior Art
It is known in connection with drive units in vehicles or with stationary installations and the like, wherein starting operations cannot be clearly noticed, to provide starting devices which are equipped with a so-called start blocking relay and/or a start repeat relay (Kraftfahrtechnisches Taschenbuch [Technical Motor Vehicle Handbook], Bosch, 18th ed., page 373). The start blocking relay protects the starter, the pinion and the engine ring gear against overloads. It automatically turns off the starter device once the engine is running on its own. It dependably prevents the actuation of the starter device while the a engine is running. The start repeat relay protects the engagement relay of the starter against overloads in vehicles in which the start-up of the engine cannot be noticed, for example in connection with rear engines or engines under the floorboards, with stationary installations with remote control and with engines which are started indirectly, for example when a defined oil pressure or a defined pressure has been reached. The start repeat relay does not act in case of normal meshing of the starter pinion with the ring gear of the internal combustion engine. However, if in connection with so-called blind switching the pinion does not find the tooth gap of the ring gear, no contact with the main current is made in spite of the switched-on meshing relay. So that during extended actuation of the starter switch the meshing coil of the meshing relay is not overloaded and burned, the start repeat relay automatically interrupts the starting process and activates it again later. In known circuits this takes place with the aid of a delayed opening relay until the pinion has meshed with the ring gear and the main current contact has been made. However, a start repeat relay of this kind can only be used with types of starters whose main current coil has an additional output terminal (terminal 48) for a connecting line to a timer circuit capacitor in the start repeat relay. Refitting with the known start repeat relay of starters without this terminal is not possible.
Because this additional connecting terminal makes the starter device more expensive and makes the application more difficult, for the purpose of a start repeat the present invention attempts to detect blind switching of sliding-gear starters without the additional terminal by means of a novel circuit arrangement and a novel method.